Q:
What are Insulating Concrete Forms?
A: Insulating Concrete Forms (ICFs) are hollow blocks or panels made of
EPS (expanded polystyrene) plastic foam that construction crews stack
into the shape of the exterior walls of a residential or commercial
building. Workers then add reinforcing steel and fill the gap (typically
101mm to 203mm) between the two layers of foam with concrete, which
cures and hardens into a monolithic core. The foam panel stays in place.
This combination of concrete, steel and foam creates an incredibly
strong and energy-efficient structure.
Q: How does
the homeowner benefit from this type of construction?
A: Homes built with ICFs offer resistance to natural disasters such as
tornadoes, hurricanes, earthquakes, fires and floods. An ECO-Block home
can dramatically reduce heating and cooling bills, plus provide an
exceptionally comfortable and quiet indoor environment.
Q: What are
the design possibilities and/or limitations with ECO-Block?
A: Today’s concrete homes can be created with virtually any design or
architectural feature. ECO-Block has furring strips every 200mm imbedded
in the panel to allow attachment of any finish — such as wood or
aluminium siding, brick, stucco and stone on the exterior, and drywall
or plaster on the interior. The result is a home that looks like any
other structure in the neighbourhood but has all the benefits of solid
concrete construction.
Q: Does it
cost more to build this way?
A: Typically, a home built with ICFs will cost slightly more than a
comparable wood-frame home. However, much or all of this cost can be
recouped through significantly lower utility and energy bills, insurance
savings and downsizing of heating and cooling equipment. An experienced
ICF contractor may be able to further reduce the costs of construction.
Q: Is
ECO-Block a difficult system for a builder to learn?
A: Conventional homebuilding crews adapt easily to ICF construction.
Most of the work involved draws on standard carpentry skills and tools.
The foam forms are lightweight, and power equipment moves the concrete.
Q: How well
do ECO-Block walls hold up in a fire?
A: Experience shows that concrete structures are far more likely to
remain standing through fire than are structures built of other
materials. Concrete does not break down until it is exposed to thousands
of degrees Fahrenheit — far hotter than a typical house fire. In
“firewall” tests, ECO-Block walls were subjected to continuous gas
flames and temperatures of up to 2,000°F for as long as four hours. None
of the ICF walls ever failed structurally, in contrast to wood-frame
walls, which typically collapse in one hour or less.
Q: What is
the average R-value of ICF walls?
A: Walls made of ICFs perform, on average, like a wood-frame wall
constructed with R-3.780 insulation. But that’s not the whole story. The
equivalent R-value performance of ICFs consists of three factors. First
is the R-value of the expanded polystyrene. Second, the thermal
stability of massive concrete walls reduces the temperature fluctuations
and, consequently, the heat load requirements that are images to
wood-frame buildings. Finally, air leakage (infiltration) can account
for 20 to 40 percent of the heat load requirements of a wood-frame
building. ICFs eliminate this air infiltration through the wall
assembly. As a result, with the combined performance of the R-value of
the expanded polystyrene, the stabilizing effects of the thermal mass of
the concrete, and the reduced air infiltration.
Q: Won’t the
foam burn or give off harmful emissions?
A: The foams in ICFs are manufactured with flame-retardant additives.
The National Research Council reviewed the numerous existing studies of
fire emissions and concluded that the emissions from polystyrene foams
are no more toxic than those of typical softwoods used in home
construction.
Q: What about
comfort?
A: Concrete walls built with ICFs effectively buffer a house’s interior
from the outdoors. The thick ICF sandwich of a massive material
(concrete) with a light one (foam) sharply cuts fluctuations in
temperature, air infiltration and noise. ICFs keep the inside more
comfortable and less drafty than ordinary wood-frame walls. With regard
to noise, studies have shown that compared to a typical wood-frame
house, only about one-third as much sound penetrates an ICF wall.
Q: How do
ECO-Block homes resist tornado and hurricane-force winds?
A: Debris driven by high winds presents the greatest hazard to
homeowners and their property during tornadoes and hurricanes. Recent
laboratory testing at Texas Tech University compared the impact
resistance of residential concrete wall construction to conventionally
framed walls. Only concrete wall systems, such as ICFs and concrete
masonry, successfully demonstrated the strength and mass to resist the
impact of wind-driven debris. The wood-frame walls failed to stop the
penetration of airborne hazards.
Q: Is this
building technique approved by code organizations?
A: Yes. Eco Block meets the requirements of the Building Code of
Australia. The 2000 and 2003 International Residential Codes have a
section on ICF construction.
Q: Can
ECO-Block homes be built in earthquake areas?
A: Yes. If properly reinforced, an ICF home can provide significant
protection during earthquakes. If you live in an earthquake zone, you
should consult a structural engineer to determine what the reinforcement
requirements are in your area.
Q: Is
ECO-Block considered an environmentally friendly method of building?
A: In a building’s life cycle (from construction to demolition); the
greatest ecological impact is the amount of fuel needed to heat and cool
the home. Insulating Concrete Homes are a preferred environmental choice
because of significant savings in natural resources needed to maintain a
comfortable temperature. Building with Eco Block (ICF’s) reduces by up
to 40% the consumption of green house gas emissions.
Q: Is it
difficult for subcontractors to work with this material?
A: No. Subcontractors — such as electricians, plumbers and drywallers —
can easily adapt to working in a house with ICF walls. Once they are
familiar with the product, many trades people actually find it easier
than working on a wood-frame home, brick and block construction.
EG NO CHASING THOUGH OUT BRICKS TO CREATE PENETRATIONS FOR PIPING OR
WIRING
Q: Can
ECO-Block be used for tilt-up applications?
A: Yes. The ECO-Block system for insulating tilt-up concrete panels
offers the speed of tilt-up construction with the benefits of an ICF
wall. After setting the panels in the form, you install reinforcement
and embed, and place the concrete. Once the concrete achieves the
specified strength, the wall is lifted in place and screw-ties directly
to the web system on the panel. For each additional inch of concrete
penetration, attach 25mm extensions to the web.
Q: Can
termites eat through the foam in an ECO-Block wall?
A: Expanded polystyrene (EPS) has no nutritive value to insects,
including termites. If left exposed and untreated, they may attempt to
nest in the EPS foam. Foam is approved for use below grade, as well as
above grade, by all building codes as long as “an approved method” of
protecting the foam plastic and structure from termite damage is
provided. Deciding what constitutes an approved method, however, is left
to local code officials.
One measure agreed upon by all parties is
the need for a minimum 152mm bare concrete inspection strip at grade
level. This is required if foam is used below grade or only above grade.
This is extremely easy to accomplish with ECO-Block, since it is a
panelised system. A 152mm horizontal strip of EPS is cut out to allow
the formation of a solid concrete barrier at grade. This creates a solid
concrete barrier, forcing the termite to the outside of the foam where
it is visible.
Additional steps, together or separately, may meet the “approved method”
requirements:
• Protect the foam with a termite barrier made from stainless steel
mesh.
• Install “bait systems” on exposed concrete strips or treat the soil as
usual.
• Treat footings and backfill with termiticides.
• Eliminate as much wood in the structure as possible by using steel and
plastic replacements.
Remember, in a solid concrete home there
is little to eat. The concrete also acts as a solid barrier to termite
infestation inside the home.
Q: Will it
take longer to build my home with ECO-Block?
A: Experienced ICF crews report that building ICF homes can actually
take less time than using wood-frame construction. The ICF construction
method eliminates several steps — such as sheathing and insulating the
exterior walls — that are necessary with wood-frame construction.
WE HAVE BUILT SINGLE STORY HOMES IN UNDER 6 DAYS
OR INSTALLED THE EQUIVALENT OF 25,000 BRICKS IN JUST 10 DAYS WITH 4 MEN
INCLUDING THE PLACEMENT OF CONCRETE
Q: Can I
leave ECO-Block exposed to ultraviolet rays for extended periods of
time?
A: Exposure of up to a year should not pose a serious problem. However,
a light oxidation layer will develop on the surface of the forms after
extended periods of exposure. This oxidation does not indicate any
detrimental effects to the wall form. However, you may need to use a
water spray to clean the oxidized layer prior to brushing the surface
with a broom to provide a clean bonding surface.
Q: When
building with ECO-Block, will mold and mildew in my new building be a
problem?
A: ECO-Block ICFs can significantly contribute to a mould-free
environment due to the inorganic nature of the material. They also
create a very tight building envelope, reducing unintentional air
infiltration. In high-humidity environments, interior moisture should
then be controlled through the use of spot removal (e.g., bathroom fans)
and properly sized air conditioning units that will cycle on long enough
to dehumidify the air.
Q: Can radius
and angled walls be constructed with ECO-Block ICFs?
Radius walls are easily constructed by mitre-cutting the form at the
proper angle and using foam to join the edges.
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